Vitamin A derivatives, such as Retin A increase epidermal thickness. Experimental evidence in animals suggest that topical application of 7-dehydrocholesterol (provitamin D3) enhances the vitamin A-induced increase in epidermal thickness. This study will evaluate the combined effects of topical 7-dehydrocholesterol and vitamin A palmitate on the epidermis in humans. Two groups of twenty will be studied using a double-blinded placebo controlled system over a period of three months.